Method of freezing food



June 5, 1951 w. l.. MORRISON METHOD 0F FREEZING FOOD Filed June 5, 1948 c: z: n@ n:

. ,l 3 X of /l /I l/ Patented June 5, i951 UNITED STAT-ES PATENT OFFICE METHOD OF FREEZING FOOD Willard L. Morrison, Highland Park, Ill.

Application June 3, 1948, Serial No. 30,929

(Cl. (i2- 173) 1 Claim. l

My invention relates to a method of freezing food in a shipping container and has for one .purpose to provide a means that will circulate the cooling convection fluid with great velocity.

Another purpose is to provide a freezing means that will so to speak, brush the heat off the food containers.

Another purpose is to circulate a cooling fluid with great rapidity so that the freezing time is reduced.

Another purpose is to utilize the cooling fluid While it is at its coldest point.

Other purposes will appear from time to time in the course of the specification and claim.

I illustrate my invention more or less diagrammatically in the accompanying drawing wherein I show a vertical section A the shipping container and the head that ts on the container during freezing.

Like parts are throughout.

A shipping container indicated as A consisting of an inner wall A-I, and an outer wall A--2, with insulation A-3 between, has for its upper lip a sealing rim l. A head containing a freezing circulatory system is indicated as B and it may be applied to the upper rim l of the shipping container. On its lower edge is a soft sponge rubber gasket 2 to make an air-tight seal as to prevent frost from being created along the meeting place.

Inside the shipping container A are the diffuser food containers 3. They are long and narrow and are loosely assembled with air spaces 4 between them. These spaces 4 are provided so 'that the cooling refrigerant may flow over the surface of the food containers thus removing heat. As the food freezes it expands and gradually fills up the spaces 4.

The cooling fluid is reduced in temperature in two stages. The tube C circulates propane to reduce the convection fluid in the first step. The tube D circulates ethylene to reduce the convection fluid in the second step. The convection fluid, in the case as illustrated alcohol, though it might be any other suitable liquid or gas as desired, even air might be used, flows in the tubes ,5. It is cooled by the propane in space 6 surrounding the tubes 5. It is further cooled by the ethylene circulating through the space 1 which also surrounds the tubes 5. The alcohol has now been reduced to extremely low temperatures and a tube -A carries it to a drop pan or distributor 8. This pan 8 is rectangular and of a size to t within the lip of the shipper container A. The lower side is corrugated with a series of small openings 9 on the outer curve of the corrugations. This design was chosen so as to distribute the convection fluid evenly over the top of the shipping container. The fluid passes through the indicated by like symbols small openings 9 if a liquid like rain but if a gas, in the form of a multitude of small jets, and passes down between the food containers 3 in the spaces 4. The iiuid is removed from the bottom pf the shipping container after it has done its work through suction tube 5B, by a pump H and recirculated through vthe cooling chambers 6 and l.

The refrigeration system is not shown because it does not constitute a part of this invention. C is the liquid line of the propane circuit and CI is the return line to the propane compressor. D Vrepresents the liquid line of the ethylene refrigeration circuit and D-l is the return line to the ethylene compressor.

It will be realized that, whereas, I have described and illustrated a practical and operative device, nevertheless many changes may be made in the size, shape, number and disposition of fparts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting 4me to my precise showing.

It will be understood that the shipping container A is a self-contained liquid-tight receptacle. After the contents have been frozen, the head B of the freezing system is withdrawn, leaving the frozen contents in situ in the separate ,diffuser receptables. An insulating cover will be placed on the container and the container with the diffuser receptacles will be shipped as a unit. It will further be understood that in the diagrammatic showing there is substantial exaggeration of the space between the diffuser containers. .When they are packed in the shipping box or container before they are frozen, they are out of contact with one another. This leaves space for the downward travel of the liquid along the conducting surfaces of the diffuser containers and permits withdrawal of the liquid from the bottom of the'receptacle. As freezing takes place, the contents of each can expands, the air space dei creases until there is some substantial measure of contact of the various cans, one with another, so that the metallic conducting surfaces of the diffuser boxes insures a uniform heat rise as heat is lost, as of course it must be, through the insulated walls of the shipping container walls A.

The use and operation of my invention are as follows:

In the freezing of food in the shipping container it is desirable to distribute the cooling convection fluid as rapidly as possible over the food containers. By this multiplicity of small 'lopenings 9 the diffusion fluid practically rains on the difusers. The fluid brushes the sides and wipes the heat away as it drops to the bottom of the shipping container. The spent iiuid is then 6o rapidly withdrawn so that none with heat in it,

remains in the box. This is an improvement over immersion in a fluid both because under these circumstances, unless the uid is consistently withdrawn, the container will be surrounded by uid which has absorbed heat thus decreasing the coolanteffect-by virtue of heat in the coolant. It is also an improvement because with immersion of the food containers the containers would have a tendency to iloat. This buoyancy cou1d be quite bothersome at the top of the shipper. The uid is rapidly circulated back tothe cooling chambers 6 and 1 where the propane and ethylene recool it, so that it can again make its circuit through the shipping container.

I claim:

The .method of.. packing. and Shipping. foodstuffs andV the likevv which consists in 'loosely assembling a plurality of insulatedmetallic,Y diffuser boxes, each of whichV is sulo,,stantiallyV lled with the food to be frozen in an insulating. Shipping receptacle, there being` clearance. between adjacent diiuser boxes for the. passage of refrigerating uid, then owing refrigerating fluid over all of the diffuser.. boxes from topto. bottom, withdrawing the refrigerating fluid` from the bottom of the shipping receptacle. and continuing this process until the contents of the diuser boxes has frozen and the freezing of the contents has expanded the boxes to decrease the clearance between and cause Contact between ladjacent boxes, then withdrawing the refrigerating uid from the shipping receptacle andclosing it with the diffuser boxes and their frozen contents therein, for shipping and storing.

WILLARD L. MORRISON.

REFERENCES CITED UNITED STATESV PATENTS Number Name. Y i Date..V

Re. 15,683 Petersen Sept. 4, 1923 1,509,850 Thompson Sept. 3Q, 1924 1,586,898 Haslacher June. 1, 1926 2,053,687. Leopald Sept. :8, 193.6 2,131,131 Zarotschenzeff Sept. 27., 1938 2,239,482 Cocks Apr. 22, 1941 2,254,406 Zarotschenzeif Sept. 2, 19.41 2,286,225 Noyes JunellG, 19.42 2,496,755.

Schwartzberg Feb. 7, 1950 

